1. Field of the Invention
The present invention relates to a lens barrel and an image pickup apparatus.
2. Description of the Related Art
A lens barrel of an image pickup apparatus such as a digital still camera is provided, in which a zoom lens moves in an optical-axis direction for a zooming operation.
Such a lens barrel includes a moving frame which supports a lens and has a cam pin, a linear-movement guide ring which guides the moving frame non-rotatably around an optical axis of the lens but movably in the optical-axis direction, and a cam ring which has a cam groove in a peripheral surface of the cam ring and which is supported by the linear-movement guide ring non-movably in the optical-axis direction but rotatably around the optical axis, the cam pin of the moving frame engaging with the cam groove.
In the lens barrel, an engagement pawl (bayonet pawl) provided at the linear-movement guide ring engages with an engagement groove (bayonet groove) formed in the peripheral surface of the cam ring to extend in a circumferential direction of the peripheral surface, and hence, the cam ring is supported by the linear-movement guide ring. When the cam ring is rotated, the moving frame moves in the optical-axis direction via the cam groove and the cam pin.
Meanwhile, in recent years, a compact and high-performance image pickup apparatus is demanded. Thus, a lens barrel advantageous to providing a high zoom ratio and reducing the size is desired. It is therefore necessary to reduce the size of the cam ring while a moving amount of the moving frame is sufficiently provided.
Regarding the situation, a lens barrel has been suggested (see Japanese Unexamined Patent Application Publication No. 2007-94118), in which a cam groove of a cam ring intersects with an engagement groove, thereby reducing the size of the cam ring in an optical-axis direction.